The rotatably supported parts of an electrical machine, such as the rotor of an electric motor, are typically supported in ball bearings. When the direction of rotation of the rotor changes, bearings of this type can produce noises that are disruptive and negatively affect comfort. The disruptive noises are produced because the balls in the ball bearing start to travel when the direction of rotation of the rotor changes and strike the other race shoulder of the bearing shell of the ball bearing. The noise is amplified further by the fact that rotor oscillations occur when the direction of rotation of the rotor changes, the rotor oscillations then being transferred to the housing of the electrical machine.